Duplicator for machine tools



Oct. 2l, 1941.

C. JOHNSON DUPLICATOR FOR MACHINE TOOLS f Filed Oct. 6, 1939 5Sheets-Sheet 1 flrrr nventor CLARENCE .JOHNSON 0d. 21, 1941. A CJvOHNsoN 2,259,472

DUPLICATORFOR MACHINE TOOLS Filed 0G11. 6, 1959 5 Sheets-511861I 2nventor CLARENC' JoHNjsoN Cttorueg C. JOHNSON D'UPLICATOR FOR MACHINETOOLS Oct. 21, 1941.

5 sheets-sheet s' `Filed Oct. 5, 1959 FIG. 3

nvlentor CLARENCE JOHNSON Gttorncu DUPLICATOR FOR MACHINE TOOLS Filedoct. 61939 5 shets-sheet 4 Ihwcnto-r FIG. 7 CLARENCE `JOHNSON 'frQM/Gimmy Oct. 21, 1941. c. JOHNSON 2,259,472

DUPLICATOR FOR MACHINE TOOLS Filed OCT.. 6, 1959 SheehtS-Shee'f, 5

Bimenor CLARENCE JOHNSON FIG. 9 1 @www Patented cm-2l, A1941 Y.: Y l

oFFlcEff nnmoa'ron Fon MACHINE TooLs Clarence Johnson, ClevelandHeights, Ohio, as

e signor to Bailey lMeter 0o of Delaware mpany, a corporationapplication october s, 1939, serial No. 298,290

" `9 claims. '(oi. en -13.5)

This invention'relates to duplicatorsior controlling the operation of amachine tool so that it forms a work piece to a contour or conilgura-`tion determined by a template or cam.

One of the objects of Amy invention is toim 5 prove the sensitivityofduplicators ci the type described and thereby increase the accuracy withwhich the Work piece is formed. i

A further object oi' my invention is to provide av duplicator ofmaterially simpler construction 10 than those now available,

A further object of my invention is to provide a duplicator .employingno moving parts in the feeler. mechanism scanning the template or cam.

In accordance with my invention the template l5 or camior producing thedesired coniiguration on the work piece is scanned by a jet of fluid is-I suing from a nozzle so that variations in the shape of the templatecause corresponding changes in the uid discharged from the nozzle, whichchanges in turn control' the positioning of the tool relative to thework piece.

Further,. in accordance with my 'invention changes in the fluiddischarged from the nozzle eiect corresponding variations in thepressure of the fluid in the nozzle, which lattervariations are used tocontrol the relative positioning oi' the tool and work piece.

Further, in accordance with my invention the changes in iluid pressurecontrol the relative positioning of the tool and work piece through ahydraulic relay and` servo-motor, to the end that ample power isavailable for accurately positioning the tool relative to the workpiece.

' Obviously a duplicator of the type forming the 35 subject matter of myinvention may be employed with machine tools of various types, such asmilling machines, lathes, slotters, planers,and other types in which therelative feed between the cutl ter and work may lne-suitably controlled.By way 40 of example I will illustrate and describe my invention asapplied totwo speciiic-types of machine tools. (Further applications andmodiilcations of my invention will be readily apparent.

In the drawings:

Fig. 1 is a side elevation and Fig. 2 is a front elevation of a verticalmilling machine illustrating the application of my invention thereto.

Fig. 3 is a sectional view taken along the line 3-3 of Figs. 1 and 2 inthedirection of the arrows. s

Fig. 4 illustrates a modified form of nozzle scanning mechanism. l

Fig. 5 is a cross sectional view of a pilot valve for controlling `thenow of fluid to and from a 55 -face extending around its entirehydraulic servo-motor for regulating the relative feed ofthe tool andwork piece.

Fig. illustrates diagrammatically a modified form of iluid pressuresystem. l Fig. 7 is a side elevation and Fig. 8 is a plan view of an'engine lathe showing the application .of my invention thereto.

Fig. 9 illustrates a further embodiment of my invention incorporating amodiiication.

Referring now to Figs. 1,l 2 and 3, I therein show a vertical millingmachine having a column I, a work table 2, and a rotatable form millingcutter 3. The work table 2 is carried in a saddle l mounted onhorizontal guideways 5 carried by a knee 6 which is supported invertical guideways 'I formed on the column I. A micrometer hand wheel 8is provided for positioning the saddle 4 along the' guideways 5. Asimilar hand wheel 9 is provided for positioning the knee 6 along thevertical guideways 1. The work table 2 is mounted on a horizontalguideway I0 formed in .the saddle 4 and is positionable relative theretoby a lead screw II. The cutter 3 is .secured to a spindle I2 rotated bya motor I3, which may be further adapted to position the work table 2along one or more ofthe guideways as is well known.

At I4 is shown a typical work piece consisting of a concave forging ofmore or less elliptical shape and in rough form having a raised blankperiphery. 'Ihe machiningV operation which I have chosen to illustratemy invention includes forming a male flange tace on this outer face. Thecutter 3 is ils1ziirtiably shaped to relieve the outer edge of the gautomatically moved relative to the cutter so that the latter accuratelyforms the outer pro- Xille oi.' the raised portion of the ange.

l. The work pieceA I4 is shown as being secured to a nxture I5 byadjustable clamping means I6. Becausev of the nature of the machiningoperation to be performed the fixture I 5 is mounted on a circular tableI1 secured to the work table 2 and rotatable at desired speed by themotor I3 through suitable reducing gears and shafting (not shown). Themachining of the work piece Il is completed in one revolution of thecircular table I'I, during the revolution the work piece being movedrelative to the cutter 3 to accurately profile the male flange by meansnow to be described. l

The iixture I5 has a horizontally extending skirt I3 forming a cam ortemplate, the contour of which is formed toproduce the desired conandb'y my invention the work piece isl tour of the raised portion of theflange on the work piece I4. A raised barrier 20 is preferably employedto hold chips cut from the work piece from scattering.

Fastened to the column I is an arm 2| in which is journaled a nozzle 22.Secured to the nozzle is an extension 23 which pivotally supports afollower 24 having a projection 25 urged against the cam or template I9by a spring 28.

The nozzle 22 lis preferably resiliently joumaled in the arm 2| by meansof spaced collars 21 and spring 28, which provide for lateral movements,thereby preventing injury to the nozzle in the event that the follower24 isinadvertently.

Normally the rate of discharge of fluid therefrom. That is to say, whenthe follower 24 is positioned to the left, or closer to the port 3|, asshown in Fig. 3, the rate of discharge from the port is decreased,whereas when the follower 24 is positioned to the right, or away fromthe port, the rate of discharge from the nozzle increases; Such changesin the rate of discharge from Athe port effect corresponding changes inthe pressure of the fluid within thenozzle, a decrease in the rate ofdischarge effectingV an increase in the pressure of the fluid within thenozzle, whereas an increase in the rate of discharge effects acorresponding decrease in fluid pressure.

As the template I9 and the work piece I4 are rotated by the circulartable I1 the follower 24 will be positioned toward and away from theport 3| in 4accordance with changes in the configuration of thetemplate. Such positioning of the follower 24 effects changes in thepressure of the uidwithin the nozzle 22. These pressure variations areeffective for positioning the work table 2, to return the follower 24 tothe normal distance from the port 37|. Inasmuch as in the embodiment ofmy invention illustrated in Figs. 1, 2 and 3 the cutter 3 is stationary,as is alsothe nozzle 22, it follows that if the work table 2 ispositioned to maintain a normal distance between the follower 24 andport 3| the work piece I4 will upon completion of the machiningoperaytion have a configuration determined by the cony figuration of thetemplate I9.

vIlnasmuch as the circular table I1 rotates, whereas ther work piece mayhave a shape other than circular, and furthermore may not beconcentrically located V,on the table withv respect to the center ofrotation thereof, it follows that the periphery of the work piece willnot be a duplicate of that of the tenplate I9. 'I'he proper contour ofthe template to give the desired shape to the work piece may bedetermined, as' evident to those skilled in the art, by calculation orgraphically. h

Changes in the shape and size of the projection'25 relative. to that ofthe cutter 3 will also modify the shape of the template I9 necessary .toproduce a desired shape of the work piece I4. In some instances thedesign ofthe template I9 is somewhat simplified vby having theprojection 25vthe same shape and size as the 'cutter 3, and therefore Iusually find it desirable to employ the construction shown in Fig. 3.However, in somev j Pressures establishedwithin the nozzle 22 are.

transmitted through a flexible tube 33 to a relay within a protectinghousing 33A and shown in cross section in Fig.*5. The tube 33 connectswith the interior of a bellows 32 secured to a wall of the housing 33A.The force produced by the fluid pressure acts against the lower or freehead of the bellows and is opposed by the inherent resiliency of thebellows and by an elliptical spring 35. The free head o'f the bellowswill therefore assume a position corresponding to the magnitude offthefluid pressure. Movements of the lower head of the `bellows position amovable valve member 36Al of a hydraulic pilot valve 36 to control theflow of hydraulic fluid to and from a servo-motor 38 having a piston 31operating the lead screw II through a rack 39, spur` gears 48, A

and a final gear 4| which is splined to the lead screw to permitrelative axial movement.

Assuming now 'that the normal distance exists between the port 3| andfollower 24 a definite pressure will exist within the bellows 32, whichby adjustment of the spring 35 will cause the valve'member 36A to assumea neutral position, i. e. a position in which no hydraulic fluid passesbetween the pilot valve 36 and servo-motor 38. If now the follower 24moves toward the port 3| the pressure within the bellows 32 willincrease,

causing a downward positioning of the valve member 36A, a passage ofhydraulic fluid between the pilot valve 36and servo-motor 38 causing thepiston 31 to move the work table 2 in a direction to restore the port 3iand follower 24 to normal distance. Upon a decrease in fluid pressurewithiin the bellows 32 the servo-motor 38 will posi- -I9 the follower 24may be moved toward and away from the port 3| as the circular table I1revolves to effect corresponding movements of the work table 2 relativeto the cutter 3 to effect accurate shaping of the work piece I4.

Hydraulic fluid, such as oil, used in positioning the piston 31 of theservo-motor 38 may be pumped by any suitable means, such as the oil pump43 driven by a motor 44. The pump 43 is provided with an inlet pipe 45extending into an oil reservoir 46, and a discharge pipe 41 which isconnected to the inlet port 60 of the pilot valve 36. Hydraulic fluidreturned from the servo-motor 38 to the pilot valve is passed to thereservoir 46 through exhaust pipes 48 and 49.

The pilot valve 35 is provided with outlet ports 50 and 5I. The formerbeing in communication with one side of the piston 31 through a pipe 52,and the latter in communication with the opposite side ofthe pistonthrough a pipe 53.r

k Downward positioning of the valve member 36A connects the outlet port50 to the pump 43 and the outlet port 5I with the exhaust pipe 49,whereas upward positioning of the valve member connects the outlet pipe5| with the pump 43 `and the outlet port 50 with the exhaust pipe 48.

The movable valve member 36A is provided with sealing glands 55 and 56,which are of sub- Other than this abitative 4 A 3 stantially the samediameter as the passageway 51 extending longitudinally through the pilotvalve.

Oil from the pump 43 admitted under pressure through pipe 41 to theinlet port 60 which is in i The. port 63 5 `is in communication withthe, passageway 51 the form of an annular chamber.

through a plurality of equally spaced upper V- ports 3| and a similarplurality of lower V-ports 32. With the valve member 36A in the neutralposition, that is in the position occupiedI when.

the follower 24 is the normal distance from the port 3|,` then a land 64restricts communication between V-ports 6| and outlet port 56. Likewisea-land restricts communication between V- ports 62 and outlet port 5|.

for example, the V-ports 6|.. are partially uncovered so thatcommunication is established between the inlet pipe 41 and the outletport 53.

The area of the uncovered V-ports 6| depends 20 upon the displacement ofthe valve member 36A from 'the neutral position, and accordingly thevilow of oil from the inlet pipe 41 to the outlet port Awill varydepending upon the displacement of the valve member. Conversely upon up-25 ward positioning of the valve member 36A from v the neutral position'a portion ofthe V-ports 62 will be uncovered, thereby permitting aproportionate flow of pressure fluid from the inlet pipe 41 tothe outletport 5|.

90 Also carried by the valve member 36A are lands u 66 and 61cooperating with spaced V-ports' 63 and 69 respectively to control theflow of pressure fluid from the outlet port 5|! to the Aexhaust pipe 43,and from the outlet port 5| to the exhaust4 35 pipe 49. It will be notedthat upon downward positioning of the valve member 36A, whichvestablishes communication between the inlet pipe 41 and outlet port 50,communication is likewise established betweenthe outlet port 5| and ex-40 haust pipe 49. Pressureuid is thus transmitted through pipe 52 to oneside of the piston 31 and simultaneously withdrawn from the oppositeside of the piston through pipe 53 to exhaust port 49. Upwardpositioning of the valve member 45 withdrawn from the opposite side ofpiston 31.50

through pipe 52 to outlet port 5|), and thence to exhaust pipe 43..Itwill be noted that whenever the valve member 36A is in other than theneutral position, the piston 31 will continue to move in predetermineddirection. Accordingly, upon the 55 follower 24 being in other than thenormal position, the work table 2, and the work piece I4 will' bepositioned until normal distanceis 're-1 stored. It is-further evidentthat the rate at which the table Y2 will be positioned will be de- 60pendent upon the amount of displacement of the follower 24 from thenormal position relative to the port 3|. If a sudden change in contourof template I3 occurs, the table 2 Vwill be rapidly positioned but upona relatively slow rate of 6 5 change in the contour ci! the template acorrespondinglyslow change in position of the table 2 will occur. Thusthe pilot valve 33 will 'cause the work-piece to be 'accuratelypositioned relative to the cutter without overshooting or hunting.

Preferablyl the sealing lands 55 and 56 are of substantially the samediameter as the passageway .51, thereby preventing materialleakage ofoil. The lands 64, 65, 63 Jand. 31 arev however of a `somewhat lessdiameter than the passage- When, however, .-15 the valve member36Aispositioned downwardly,

way 51, thereby preventing undue friction and permitting the member 36Ato be freely positionedvin the passageway. The pressure transmitted fromthe inlet pipe 41 to outlet ports 50 and 5|, with the member 36A inneutral position,

-because the lands 34 and 65 may be of somewhat less diameter than thepassageway, will not affect the accuracy with which the piston 31 ispositioned for such pressures will be equal and act in oppositedirection on the piston 31. It will further be noted that the ows intoand out of the passageway 51 are radial. vso that there is no reactionon the member 36A because of the velocity of iiow into and out of thepassageway. Furthermore, the pressures are axially balanced due to theequalareas of lands 64. 65, 66 and ,61 so that no reaction exists due tothe resultant of the oil pressures acting in an upward or downwarddirection.

While in general I have found it preferable to operate the table 2 orcomparable device indirectly from the fluid pressures established withinthe nozzle 22 by means of a hydraulic relay, in

some instances where a relatively light machining operation is beingperformed, or an extreme degree of accuracy is not required, I havefound it possible to dispense with the hydraulic relay system and employin its stead a pneumatic relay system as shown in Fig. 6.

Therein I show iiuid pressure, such as compressed air, transmitted fromthe pipe 29 ahead of the oriilce 30 to a pilot valve 10 by a pipe 1|.

\The pilot 10 .shown in cross-section 'may be so constructed thatdownwardI positioning of the movable valve member 12 permits pressurefluid to be transmitted to one side of the piston 31 and simultaneouslyexhausts pressure fluid from the opposite side or the piston 31.Conversely upon 'upward positioning of the member` 12 reverse operationvof the piston 31 will occur. When the normaldistance exists betweenport 3| and template I3 the member 12 is positioned sc that the landsthereon are adjacent the outlet ports dleading to the servo-motor 38.

In the embodiments of my invention so far described the work piece hasbeen moved, whereas the cutter or. tool has remained stationary.

In Figs. 'I and 8 I disclose a. further embodiment,

of my invention in conjunction with an engine lathe wherein the workpiece remains in ilxed position and the tool... or cutter, is moved. Itwill .be evident to those skilled in the art however that in all ofV,the embodiments it is the relative movement between the work piece-and the tool which is of importance and which is controlled by myinvention.

v -Referring to Figs. '1 and 8 I therein show a typical engine lathehaving a bed 30, rotatable face plate 3|. and tail stock 32. It isfurther provided with a carriage 33 movable on guideways 34, 35longitudinally along the bed 3D. Normally the longitudinal movement ofthe carriage is controlled by a feed screw 36, which may be driven byany suitable source of power (not shown) at any desired speed by meansof suitn able reducing gears (not shown).

Mounted on the carriage 83 is a cross-slide 81 carrying a tool holderand tool 31A which by way of example I have shown as forming a workpiece 33 into .general irregular .conical form. In the embodiment of myinvention shown the transverse motion of the cross-slide 31 isautomatically controlled so that the work piece 33 is formed tocorrespond in shape to a template 89, which is secured to the' bed 80 ofthe lathe by suitable clamping means 90.

The system for positioning the tool 81A relative to the work piece 88 issubstantially the same as that described for positioning the cutter 3relative to the Work piece I4. Nozzle 22 is resiliently mounted in anarm 9| secured to the cross-slide 81. The projection 25 of the follower24 bears against the edge of the template 89, which has a contour towhich the work piece 88 is to be shaped. Pressures established in thenozzle 22 are transmitted to the relay 33A, which in turn acts tocontrol the positioning of the piston 31 in servo-motor 38. Positioningof the piston 31 controls the transverse positioning of theItool 81through a rack 39 and suitable gears 92A.

In order that the servo-motor 38, relay 33A and associated apparatus maymove with the cross-slide81. longitudinally along the lathe they areshown mounted on a truck 92 provided with flanged wheels 93 riding onrails 94. The truck 92 is secured to the carriage 83 so that theservo-motor is maintained at proper operating distance from thecross-slide 81.

In operation, as the template 89 changes in\ shape correspondingvariations in pressure within the nozzle 22 occur, which effecttransverse operation of the cross-slide 81 to maintain the follower 24at normal dist-ance from the port 3|. Simultaneously, the tool 81A ismoved transversely so that the work-piece 88 assumes the same shape asthe template 89., The cross-slide 81 is moved longitudinally by the feedscrew 86 and carriage 83 at desired speed by any suit able source ofpower as heretofore described.

In the embodiments of my invention illusspeed reset mechanism, positionthe piston ..31 to or about its mid position. Next, I throw in theclutch |00 and then restart the machine. The operations I have describedmay be performed entirely automatically so that after the machiningoperation is once started, it is unnecessary that the operator give itany further attention until the operation is completed. l

Describing nrst the operation whereby the ead screwl IIA is declutchedlfrom the gear 4|A when the rack 39 approaches the end of its travel inone direction, a. contact |0| carried by the rack 39 engages astationary contact |02, thus clos'- ing the circuit for the coil |03 ofa solenoid |04. The solenoid has a movable armature |05 which ispositioned downwardly from its mid or neutral position by energizationof the coil |03.

The armature |05 lcarries a horizontal ext nsion |06 terminating in acontact |01'normally, that is when the coi1'I03 is not excited, engagingastationary contact |08. Theclutch |00 f as a coil |09 which holds theclutchin so that movetrated I have shown the lead screw of a machineplate occur, in order to provide corresponding movements of the workpiece relative to the tool a cylinder and rack of` too great length tobe practical was required. I have devised a system, howeverl whereby acylinder and rack of desired length may be used regardless of theconiiguration of the template. Because the novelty of my system does'not reside in any particular element, but in the novel cooperationbetween a combination of elements, I have chosen to illustrate thesystem schematically.

Referring to Fig. 9, I therein show the nozzle 22 and cooperatingtemplate I9. It will be evident that if the template I9 has largechanges in configuration in order to obtain corresponding changes' inrelative positions of the work piece and tool, it will be necessary thatthe lead screw IIA be revolved an exceptionally large number of turns,which ordinarily would require rack 39 and cylinder 38 to beimpractically long. In accordance with my invention, however, I employ arack and cylinder of desired length and when the rack is near the end ofits travelin 'either direction I declutch the lead screw IIA from the'gear 4IA by means of an electromagnetically operated clutch |00, andsimultaneously stop the machine. I then, by means of a high ments of therack 39 are transmitted to thev lead screwY IIA. When the coil |09 isdeenergized, the clutch |00 is declutched so that regardless of movementof the rack 39, the lead screw IIA remains stationary. As shown.energization of the coil |09 is controlled by contacts |01| 08. Thus,upon energization the coil |03 and the armature |05 moving downwardlyclutch |00 is opened so that thereafter until contacts |01-I08 againengage,`the lead screw I IA will remain stationary. l

So far as the operation of the clutch |00 is concerned, the samesequence of events occurs movable'valve member I|2 of a pilot valve H3.

Carried by the member ||2 are lands ||4 and ||5 normally disposed in a.closed position so that hydraulic iluid is neither transmitted to orfrom pipes II6 and 1. The pilot valve is supplied with oil underpressure from any suitable source (not shown) through an inlet port II9disposed between lands ||4 and H5. The pilot valve also has two exhaustports |20 and I2I.

positioned so that the work piece is moved rela--` tive to the tool incorrespondence with changes in the configuration of the template I9 asheretofore described. During these periods of normal operation, thearmature |05 is in the neutral position so that oil is transmittedneither to nor -from the pipes ||5 and ||1. Upon either upward ordownward movement of the armature los it wuibobserved, however, that1ands. I4

and |I5 will be displaced from the neutral position thereby permittinghydraulic iluid to be 'transmitted to one of,the pipes ||6 or |I1 andwithdrawn from the other pipe.

In operation upon the contact |0| engaging stationary contact |02, forexample. indicating that the rack 39 has reached its approximate travelend in that direction, the amature will move downwardly, therebyconnecting intion piston 31 to the right as shown in the drawlet port||9 with pipe ||1 so that hydraulic fluid will be transmitted to thecylinder 38 and posiings so that the rack is. restored to a positioncontact |'I0 engages the stationary contact |02- is similar in thisinstance to the amature |05 moving upwardly thereby connecting inletport 9 with pipe ||6 so that hydraulic uid is transmitted to pipe 52 andpositioning the rack 39 in opposite direction. Simultaneously, pipe ||1is connected with exhaust port 2| so that hydraulic iiuid is withdrawnfrom pipe 53 and the opposite side of piston 31. n

To prevent the armature |05 being restored to the neutral position ,assoon as disengagement between contact |02 and contact |0| or ||0 occursand, further, to govern the resetting of rack 39, I providea time delaymeans, in the drawings shown as adash pot |22, which may be providedwith an adjustable bleed valve |23 togovern the time required for thearmature |05 to be re' positioned to the neutral position and hence theposition to which the piston 31 will be restored after having reached anextreme of travel. Conveniently, the dash pot |22 may be provided withbiasing springs |25 to maintain the armature |05 in neutral positionduring periods of normal operation.

As will be understood by those familiar Vwith the art, I may by properdesign of pilot I3 render the relay 33A substantially inoperative duringthe period of time when the armature |05 is displaced from-the mid orneutral position. Thus, I may provide for much greater flows at higherpressures through the pilot l I3 so that the operation of the relay 33Ahas an unappreciable effect upon the positioning of the Ipiston 31Within the cylinder 38. However, I may if desired provide for isolatingthe relay 33A from the cylinder 38 during periods when the piston 31 isbeing reset.

By way of diagrammatic illustration, I show in between relay 33A andcylinder 30 is stopped. Normal communication will be reestablished wher.the armature |05 is returned to the neutral position and contacts l01,|08 reengage. .'I'hus; if preferable, I may during a reset operationisolate the cylinder l3B so that the piston 31 is controlled solely frompilot ||3.

During the reset operation, the machine is preferably `stopped toprevent the tool from` incorrectly forming the work piece while theclutch |00 is disengaged. To this end I show the motor |3A, driving themachine, as controlled from contacts |01|08. Connected in the motorcircuit is a solenoid relay |30 normally energized through contacts|01|08. When these. contacts disengage, however, solenoid |30 breaks thecirl cuit to motor ISA. Preferablymotor 3A is not restarted until ashort 4increment of time after contacts |01| 08 have reengaged. Toprovide for this I show the solenoid |30 as provided with a dash pot |3|having an adjustable bleed valve |32 so that the delay in restarting themotor |3A after closure of contacts |01| 08 may be adjusted. This timedelay in restarting motor |3A permits the tool Lto be accuratelyadjusted rela-l tive to the work piece in the event that such adjustmenthas been altered during the period of time when the reset operation istaking place.

While in accordance withthe patent statutes I have described certainembodiments my invention, it is evident that such embodiments may bemodified in many ways without departing from the spirit and scope of theinvention. Such embodiments of my invention as I have chosen to describeshould therefore be taken as merely illustrative and not as limiting. j

What I claim as new and desire to secure by Letters Patent of the UnitedStates is;

l. In aduplicator for machine tools and the like having a relativelymovable tool and work piece, means for controlling relative movementbetween the tool and work piece comprising a d port through which iluidis passed from a pres- 3o" sure supply, means responsive to the rate atwhich iluid is passed through said port for relatively moving the tooland work piece, and a template having the desired shape of the workpiece for controlling the rate at which ilud is passed through saidport.

- 2.4 In a duplicator for machine tools and the like having a relativelymovable tool and work piece, means for controlling relative' movementbetween the tool and work piece comprising a nozzle having a port toatmosphere through which fluid is continuously discharged from apressure supply, means responsive to the rate of fluid discharged fromsaid nozzle forrelatively moving the tool and work piece, and a templatehaving the 'desired shape of the` work piece mov'- able relative to saidnozzle for controlling the rate of iluid discharged from said nozzle.

3. In a duplicator for machine tools and the like having arelativelymovable tool and work piece, means for controlling relativemovement of the tool and work piece comprising a control couple oneelement of said couple forming a nozzle having a port to atmospherethrough which iluid is continuously'dis'charged from a pressure supply,and the other element of which' affords a valve for said port; relativemovement of said elements governing the discharge of pressure iluid fromsaid nozzle; means responsive to the rate of iiuid discharged from saidnozzle for relatively moving said tool and work piece, and a templatehaving the desired shapeJ of'the work piece for relatively moving saidelements.

4. In a duplicator for machine tools and the like having a relativelymovable 'tool and work. piece comprising, a template having the desiredshape of the workpiece, a. nozzle having a Port to atmosphere throughwhich fluid is continufously discharged for scanning the template, the

ing the tool and work piece.

5. In a duplicator for machine tools and the like having a relativelymovable tool and workV piece, a Itemplate having a shape correspondingto the desired shape of the work piece, a nozzle having a port toatmosphere for directing a `1ct of air against said template, means forcausing said vnozzle to scan said template whereby vari-'- ations in theshape of said template cause corresponding variations inthe rate of airdischarged from said nozzle, and means responsive to the rate of-airdischarged from said nozzle for relatively moving the tool and workpiece.

6. In a duphcator for machine tools and the like having a relativelymovable tool and work piece for yforming said work piece to desiredshape, comprising, a template having a shape l corresponding to thedesired shape of the work piece, a, nozzle having a port to atmospherefor directing a jet of air against said template so that said templatecontrols the rate of discharge from said nozzle, means for causing saidnozzle to scan said template whereby variations in the shape of saidtemplate cause corresponding variations in the rate of air dischargedfrom said nozzle, means for relatively moving said tool and work pieceLn correspondence with the scanning of said template by said nozzle, andmeans responsive to the rate of air discharged from said nozzle forrelatively moving said tool and work air to said nozzle from a source ofsupply, are-v striction 'in said passageway, means for causing saidnozzle to scan said template whereby vari' ations in the shape of saidtemplate causecorre-v sponding variations in the pressure of the air inthat portion of the passageway between said. restriction and saidnozzle, a servo-motor for' piece, nozzle means for directing a jet ofairrelatively moving said tool and work piece, and means responsive tothe pressure of the air in that portion of the passageway between saidrestriction and said nozzle for controlling the operationpf saidservo-motor.

8. A duplicator for machine tools and the like having a relativelymovable tool and Work piece for forming said work piece tov desiredshape. Y

comprising, a template having a shape corresponding to the desired shapeof the work piece, a nozzle having a port to atmosphere for directing ajet of air against said template\ sothat the template controls the rateof discharge from said nozzle, a passageway for transmitting air to saidnozzle from a source of supply, a restriction in said passageway, meansfor causing said nozzle to scan said template whereby variations in theshape oi said template cause corresponding variations in the pressure ofthe air in that portion of .the passageway between said restriction andsaid nozzle, a hydraulic servo-motor for positioning said tool relativeto .said work piece, anda pilot valve for controlling the now ofhydraulic fluid to and from said servo-motor responsive to the pressureof the air in the said portion 'of said passageway between saidrestriction and said-,.nozzle.

9. A duplicator" for machine tools and the like having'a'relativelymovable tool and work piece for' forming said work piece to desiredshape, comprising, a template having a shape corresponding to thedesired shape of the work against said template, the relative approachand recession of said nozzle and template governing the pressure .insaid nozzle, Ya servo-motor for positioning said tool relative to saidwork piece and simultaneously and in correspondence therewithpositioning said nozzle means relative to said template and meansresponsive to the air pressure in said nozzle for operating saidservoxnotor to maintain said air pressure at a predetermined value.

CLARENCE JOHNSON.

